Locking means for pressure chamber doors



April 0, 1946. w. 1.. CULLEN 2,399,327

LOCKING MEANS FOR PRESSURE CHAMBER DOORS Filed May 22, 1943 2Sheets-Sheet l 56 .[NVENTOB a) MLL/AM LLOYD CULLEN MBA/1S", K/scw,Fosrzn 5/445):

ATTORNEYS April 1946- w. CULLEN I 2,399,327

LOCKING MEANS FOR PRESSURE CHAMBER DOORS Filed May 22, 1945 2Sheets-Sheet 2 I I [NVENTOB I VV/LL/AM LLOYD CULLEN 1} H HARRIS mac/4,FosrsR @MRR/S I ii w ATTORNEYS Patented Apr. 30, 1946 LOCKING MEANS FORPRESSURE CHAMBER DOORS William Lloyd Cullen, Los Angeles, Calif.,assignmto Hughes Tool Company, Houston, Tex., a eor-' poration ofDelaware Application May 22, 1943, Serial No. 488,064

7 Claims.

- My invention relates to closure-securing means and is directedspecifically to the construction of means to lock the door of a pressurechamber.

The invention is being initially applied to the problem of locking arelatively large door through which large airplane sections must passinto a chamber for processing at superatmospheric pressure. It will beapparent, however, that the invention is widely applicable.

Since the force tending to open a circular door of a cylindricalpressure chamber varies as the square of the diameter of the door, anymeans designed for holding a relatively large door in closed positionmust be capable of withstanding forces of tremendous magnitude. If thefluid under pressure is gaseous, for example air or steam, the properdesigning of the door-retaining means is of special importance, sinceany structural failure may cost human lives.

The general object of my invention is to provide a simple, efficient,and safe means for retaining or looking such a door against fluidpressure.

One of the specific objects of my invention is to provide a door-lockingmeans having extensive zones of engagement, thereby to keep the unitstress of, the door-locking means at a low value relative to themagnitude of the total pressure against the door. In this regard, myinvention is characterized by the concept of providing a ring around thedoor adapted to expand from an inner position to an outer position, andvice versa, the ring at one of said positions providing forinterengagement between a circumferentially extensive locking surface onthe door and. a second circumferentially extensive locking surface onthe chamber.

In the preferred practice of my invention, the locking ring is split toprovide ring ends that may be moved apart to expand the ring and drawntoward each other to contract the ring. Certain objects of my inventionrelate to the provision of simple and efficient means for causing suchrelative movement between the ring ends. Among these objects are thefollowing: to provide means for multiplying manual force exerted by anoperator in moving the ring to lock the door; to provide such means inwhich the mechanical advantage for multiplication of the applied forceprogressively increases in the course of the locking operation; toprovide such means that is irreversible in the sense that thering-operating means is mechanically non-responsive to forces tending tomove the ring to its door-releasing position; and to provide such meansthat may be conveniently latched to hold the ring in its ineffectiveposition when the door is open.

In the preferred practice of my invention, a further object in mind isto provide an expansible ring that will have at least some wedgingaction to insure movement of the door to a desired closed position.

Another object of my invention is to provide a door-locking arrangementthat incorporates means to indicate whether or not the door is locked,the indicating means being perceptible at any desired point or pointsnear the door or remote from the door. Such an indicating means reducesthe possibility. of accidents, caused, for example, by introducing-fluidunder pressure into the chamber while the door is open or when thedoor-locking ring is not moved completely into its door-lockingposition.

A still further object of my invention is to provide safety means toprevent an operator from inadvertently releasing the door-locking meanswhile the chamber contains fluid at dangerous pressure.

The above and other objects and advantages of my invention will beapparent in the following description, taken with the accompanyingdrawings.

In the drawings, which are to be considered as merely illustrative:

Figure lis a plan view, partly in section, of a door at the end of acylindrical chamber incorporating my invention, the view being partlybroken away and partly in section for clarity;

Figure 2 is a diagrammatic view showing the door-locking ring and anassociated indicating circuit;

Figure 3 is an enlarged fragmentary section of the door showing thedoor-locking mechanism;

Figure 4 is a similar section showing a switch in the indicatingcircuit;

Figure 5 is a similar section, taken as indicated by the line 5-5 ofFigure 1;

Figure 6 is a fragmentary view, taken as indicated by the arrow 6 inFigure 3, a portion of the wall structure being broken away to revealthe locking mechanism; and

Figure 7 is a wiring diagram of circuit means for controllin certainsafety locks in the preferred practice of my invention. 7

The drawings illustrate the invention as applied to a large cylindricalchamber, generally designated l0, having a semi-spherica1 door, gen-'erally designated l I, that is large enough to pass large wing sectionsand other structural parts of aircraft and the like. Such a chamber maybe employed for applying pressure, or pressure together with heat, forsetting adhesive plastic in the fabrication of airplane structure.

Since such a large door for withstandin high pressure is necessarily oftremendou weight, and since it is desirable to avoid the use of hinges,it is necessary to provide some power-actuated means for moving the doorinto and out of its closed position. For this purpose, Figure 1 shows aframe structure if! welded to the door. The frame structure i2 provideson each side of the door a plate I! and two flanges l5 for slidingengagement with vertical tracks I 6 made of channel-iron. The verticaltracks are part of a doorsupporting frame IT. The door-supporting frameI! is movable toward and away from the end of the chamber l0 under theguidance of guide bars II and is provided with a suitable hoist (notshown) for elevating and lowering the door when the door-supportingframe I 1 is spaced away from the open end of the cylindrical chamber.

As indicated in Figure 3, the chamber Hi has a relatively thick entrancewall 20 to receive telescopically a cylindrical wall portion 2| of thedoor II. On the inner side of the entrance wall 28 is welded a ring 22to provide a seat for a resilient ring 23 of rubber or other suitablematerial. The resilient ring 23 is postioned to serve as a bum'ier tocushion the closing action of the door II, but ii at any time thechamber is employed to develop a vacuum, the resilient ring may functionprimarily as a sealing means, atmospheric pressure exerted over theentire area or the door serving to urge the door against the resilientring in an air-ti ht manner.

If the chamber II is placed under super-atmospheric pressure, forexample by the introduction of steam as contemplated herein, leakagefrom the interior of the chamber is prevented by a secand resilientsealing ring 25 seated in an annular recess 26 in the entrance wall 20.This second sealing ring 25 is preferably of U-shaped cross section, asindicated, to form two annular sealing lips 21 having tapered edges.Such a U-shaped sealing ring may be backed up by a metal ring 28 and mayembrace a second metal ring ID that serves to hold the two sealing lips21 apart. Fluid pressure from the interior of the chamber Ill causes thetwo sealing lips'to tlex against the adjacent metal surfaces in aliquid-tight manner. Obviously, various sealing arrangements may beemployed to retain either a vacuum or superatmospheric pressure in thechamber when the door is closed.

My invention contemplates the provision of two circumterentiallyextensive shoulders for co0per ation with an expansible ring. Oneshoulder is provided by the chamber structure and faces toward theinterior of the chamber, while the other shoulder is provided by thedoor structure and faces outwardly of the chamber. When the rin isefiective to prevent outward movement at the door in response to chamberpressure, the outwardly-facing door shoulder presses against the ringand the ring, in turn, presses against the inwardly-facing shoulder ofthe chamber structure.

As best shown in Figure 4, a chamber shoulder 3| may be formed bycutting a circumferential recess 32 on the inside oi the entrance wall20 of the chamber, while a cooperative door shoulder 33 may be providedby cutting away the material of the cylindrical wall 2! or the door.

It will be readily apparent to those skilled in the art that a ring forthe desired cooperation with the two shoulders SI and I! may be adaptedeither to expand out of engagement with the door shoulder 33 or tocontract out of engagement with the chamber shoulder 3|. In other words,the ring may either be mounted on the chamber structure to contract indiameter from an ineffective or door-releasing position intodoor-locking engagement with both the shoulders, or may be mounted onthe door for expansion in diameter from a door-releasing position intodoorlocking engagement with the two shoulders. In my preferredconstruction illustrated by the drawings, I choose to mount anexpansible ring 35 adjacent the door shoulder 33 for expansion into aposition for engaging both the door shoulder 33 and the chamber shoulderII.

The particular locking ring 35 shown in the drawings is divideddiametrically into upper and lower sections 36 and 31, respectively.Each of these two sections may carry a pin 38 (Figures 1 and 5) thatslidingly engages a radial slot II in an angular retaining clip ll.Other retaining clips 42, without such slots, may be placed at variouspoints around the door to loosely retain the locking ring 38 when thedoor is in open position.

In the present practice of the invention, I employ on each side of thedoor what may be termed a toggle lock, generally designated 0, theconstruction of which is best shown in Figures 3 and 8. Each toggle lockcomprises a pair of interconnected toggle links ll and 48, the link llbeing pivotally connected to a bracket 41 on the end of the upperlocking ring section I, and the link 48 being likewise pivotallyconnected to a bracket 48 on the lower locking ring section 31. Formanual control, the lower toggle link ll may be one arm of an operatinglever ll having a suitable handle 8|.

When the operating lever II is raised to locking position, as indicatedin Figure 6, the two toggle links 4! and I! move past center to providea positive lock with no reaction forces tending to throw the lock open.In other words, by arranging for the two toggle links to move pastcenter in expanding the ring, I provide what may be termed anirreversible linkage in the sense that any tendency of the ring sectionsto move together does not create any tendency tcrthe toggle links toswing to their door-releasing positions.

The two toggle locks 43 on opposite sides of the door are opened bysimply swinging the operating levers 50 downwardly, and, forconvenience, a suitable latch 52 may be provided to hold each togglelock open, thereby to hold the divided locking ring in radiallycontracted state. Each latch 52, as best shown in Figures 3 and 6, maycomprise simply a leaf-spring arm bent to form a suitable latchingshoulder 53 ior engagement with the associated operating lever SI, thearm being adapted for flexure out oi latching position.

Figures 1, 2, and 4 indicate how, in the preferred practice or myinvention, I may incorporate means to indicate whether or not thelooking ring 38 is in its effective position to hold the door ll closed.Four switches II may be placed at equally spaced positions around thecircumference of the entrance wall 20 of the chamber, each of theswitches having an operating plunger I8 that extends through a bore 81(Figure 4) in the entrance wall into the path of expansion of thelocking ring SI. These lour switches ll are closed only when the lockingring SI is properly expanded into its locking position so that failureof any one of the four switches to close indicates that the door II isnot properly locked.

As shown diagrammatically in Figure 2, the switches may be connected inseries by wires II, with one end or the series connected to a wire I andthe other end of the series connected to a wire I. A battery 82, orother suitable source of electromotive force, is shown with one terminalconnected to the wire 8. and the other terminal connected in parallel toindividual signal lamps i3 and t5, the two signal lamps being, in turn,individually connected to the wire II. It is apparent that, when thefour switches II are all closed by expansion of the locking ring II, the

two signal lamps i3 and BI will be energized to indicate that it is safeto introduce fluid under pressure into the chamber II. The two signallamps 63 and 65 may be at different stations, one station, for example,being near the entrance to the pressure chamber and the other stationbeing in a boiler room within sight of a valve employed for regulatingthe flow of steam into the chamber III.

In the preferred practice of my invention, 1 also incorporate suitablesafety means eifective automatically to prevent anyone frominadvertently unlocking the door while a hazardous condition exists withrespect to the interior of the chamber It, for example to prevent anyonefrom unlocking the door while the chamber is charged with fluid at adangerous pressure.

Figure 6 shows, by way of example, how the operating lever 50 may beprovided with a short extension 88 that is concentric with the axis ofrotation of the lever and is formed with a locking recess 81 forcooperation with a safety lock 8. The safety lock 68 is in the form of asolenoid mounted on the door by suitable screws II, which solenoid hasan operating plunger 1| to serve as a locking member for movement intoand out of the locking recess 61. It is contemplated that the plunger Hof the solenoid will be retracted from the locking recess when thesolenoid is de-energized and will automatically enter the recess toprevent opening movement of the lever 50 whenever the solenoid isenergized.

Figure '7 shows schematically how the two coils 12, respectively, of thetwo safety locks 80 that lie on opposite sides of the door H may beconnected in parallel between two wires ll and II. The wire I! isconnected to one terminal of a battery 11, or other suitableelectromotive source, and the other terminal of the battery is connectedto one side of a pressure-responsive switch II. The wire 16 is connectedto the other side of the switch It to complete the circuit. Wheneverfluid under pressure is introduced into the chamber it while the door IIis closed, with the two operating arms 50 in the position indicated inFigure 6. the switch ll responds to the chamber pressure by closing thecircuit shown in Figure '1, thereby energizing the two coils I! to causethe two safety locks 8| to lock the operating handles Bl against openingmovement. The safety locks it may be released only by causing thechamber pressure to drop to a safe level.

The manner in which the invention operates will be readily apparent fromthe foregoing description. when the door is moved into closed positionpreliminary to the processing of material in the chamber ID, theoperator swings each of the operating levers 50 upwardly to the positionshown in full lines in Figure 6. It will be noted that the operating arm{I is considerably longer than the toggle link ll, thereby multiplyingthe manual i'orce applied by the operator to the handle Ii. It will befurther noted that, by virtue of the toggle linkage, the are rangementprovides increasingly favorable leverage for the operator as-the handleSi is raised to fully locked position. In approaching the fully lockedposition shown in full lines in Figure 6, the two toggle links ll and Itswing past center, i. e., move the interconnectin toggle pin I! past astraight line defined by the axes of the two togslepinsllandll. v

It is to be noted in Figures 3, 4, and 5 that the expanslble ring I5 hasa wedging portion, or what may be termed a rounded leading edge It tocooperate with the chamber shoulder ii to wedge the door shut wheneverslight wedging action is required to shift the door to its final closedposition,

When it is safe to open the door after the chamber pressure has beenreduced at the end of a processing period, the operator swings the twooperating levers downwardly, thereby moving the associated parts to thepositions indicated by dotted lines in Figure 6. This downward movementcauses the operating arm 50 to be releasably engaged by the latch arm I!to hold the locking ring I! in contracted position so long as the dooris open. By providing the latch arm 52, I insure that the locking ring35 will not accidentally expand to interfere with subsequent closingaction of the door. The two latch arms 52 may be readily flexed torelease the operating handles it whenever desired.

The preferred practice of my invention described in detail herein willsuggest to those skilled in the art various changes and substitutionsunder my basic concept, and I reserve the right to all such departuresfrom my disclosure that properly lie within the scope of my appendedclaims.

I claim as my invention:

1. The combination with a door and a pressure chamber of means to loci;the door, comprising: a first shoulder on the exterior of said door.said shoulder facing outwardly of the chamber; a second shoulder on awall of the chamber, said second shoulder facing toward the interior ofthe chamber; an expansible ring adapted to expand from an inner positionto an outer position and vice versa, said ring being dimensioned toclear one of said shoulders at one of said positions and to engage'bothof said shoulders at the other of said positions, thereby to lock thedoor: and an indicating means responsive to expansion and contraction ofsaid ring to indicate whether or not the door is locked.

2. The combination with a door and a pressure chamber of means to lockthe door, comprising: a first shoulder on the exterior of said door.said shoulder facing outwardly of the chamber: a second shoulder on awall of the chamber, said second shoulder facing toward the interior ofthe chamber; an expansible ring adapted to expand from an inner positionto an outer position and vice versa, said ring being dimensioned toclear one of said shoulders at one of said positions and to engage bothof said shoulders at the other of said positions, thereby to lock thedoor; an indicating circuit; signal means controlled by said circuit toindicate whether or not the door is locked; and a plurality of switchmeans in said circuit positioned at spaced points of said rin saidswitch means being responsive to expansion and contraction of said ringfor opening and -losing said circuit.

3. The combination with a door and a pressure chamber of means to lockthe door, comprising: a first annular shoulder on the exterior of saiddoor, said shoulder facing outwardly of the chamber; a second annularshoulder on the chamber, said second shoulder facing toward the interiorof the chamber; a ring split to provide separable ends for expansion ofthe ring and contraction of the ring; means acting between saidseparable ends of the ring to expand the ring from an inner position toan outer position and vice versa, said ring at one of said positionsclearing one of said shoulders and in the other of said positionsenaging both said shoulders to hold the door in closed position; anindicating circuit; switch means in said circuit responsive to expansionand contraction of said ring to open and close said ircuit; and signalmeans controlled by said circuit to indicate whether or not said ring isin the oosition to lock the door.

4. The combination with a door and a pressure chamber of means to lockthe door, comprising:- a first annular shoulder on the exterior of saiddoor, said shoulder facing outwardly of the chamher; a second annularshoulder on the chamber, said second shoulder facing toward the interiorof the chamber; a ring split to provide separable ends for expansion ofthe ring and contraction of the ring; toggle means acting between saidseparable ends of the ring to expand the ring from an inner positionclearing said second shoulder to an outer position engaging both of saidshoulders, said toggle means being constructed and arranged to move pastcenter in expanding the ring to lock the ring against forces tending tocontract the ring; an indicating circuit; switch means in said circuitresponsive to expansion and contraction of said ring to close thecircuit when said ring is expanded into locking position; and signalmeans in said circuit to indicate when said ring is expanded intolocking position.

5. The combination with a door and a pressure chamber of means to lockthe door, comprising: a first annular shoulder on the exterior of saiddoor, said shoulder facing outwardly of the chamber; a second annularshoulder on the chamber, said second shoulder facing toward the interiorof the chamber; a ring split to provide separable ends for expansion ofthe ring and contraction f the ring; toggle means acting between --saidseparable ends of the ring to expandthe ring from 1' inner positionclearing said second shoulder to an outer position engaging both of saidshoulders, said toggle means being constructed and arranged to move pastcenter'in expanding the rin thereby to lock against forces tending tocontract the ring; an indicating circuit; switch means in said circuitresponsive to expansion and contraction of said ring to close thecircuit when said ring is expanded into locking position; signal meansin said circuit to indicate when said ring is expanded into lockingposition; and latch means to hold said toggle means in ring-contractingposition to prevent closing of said switch means and consequentenergization of said indicating circuit, thereby preventing operation ofsaid signal means when said ring is contracted into unlocking position.

6. The combination with a door and a pressure chamber of means to lockthe door, comprising: a first shoulder on the exterior of said door,said shoulder facing outwardly of the chamber; a second shoulder on awall of the chamber facing toward the interior of the chamber; a ringsplit to provide separable ends; toggle means acting between theseparable ends of the ring to expand the ring from an inner position toan outer position and vice versa, said ring at one of said positionsclearing one of said shoulders to permit opening of the door and at theother of said positions engaging both of said shoulders to lock thedoor; electrically-actuated safety means to lock said toggle meansagainst door-releasing movement; a circuit to energize said safetymeans: and a switch in said circuit, said switch being responsive topressure in said chamber to cause said safety means to lock said togglewhen the pres sure in the chamber rises above a predetermined va ue.

7. The combination with a door and a pressure chamber of means to locksaid door, comprising: a shoulder provided on the exterior of said doorand facing outwardly; another shoulder provided on a wall of saidchamber and facing inwardly: locking means adapted to be moved to innerand outer positions with respect to said shoulders, said means clearingone of said shoulders in one of said positions and engaging both' ofsaid shoulders inthe other of said positions whereby to lock said door;electrically-actuated safety means to lock said locking means indoor-locking position; a circuit to energize said safety lock; and aswitch in said circuit responsive to pressure in said chamber to causesaid safety means to lock said locking means when a predeterminedpressure develops in said chamber.

WILLIAM LLOYD CULLEN.

